Preheat oven to 375°F (190°C).

Place shredded Swiss cheese, cooked and crumbled bacon, and chopped onion evenly in the 9-inch pie crust.

In a mixing bowl, combine slightly beaten eggs, light cream, and Grey Poupon mustard.

Pour the egg mixture over the cheese, bacon, and onion in the pie crust.

Bake in the preheated oven for 35 to 40 minutes, or until a knife inserted in the filling comes out clean.

Let cool slightly before slicing and serving.